Fix kubectl version unit test

[eddiezane]

What type of PR is this?

/kind failing-test

What this PR does / why we need it:

The TestNewCmdVersionWithoutConfigFile unit test currently relies on an API server. This causes the test to fail for developers that don't have a cluster configured.

This PR swaps out the cmd factory for a testing one that does not provide a discovery client. This causes the external request bits to be skipped.

kubernetes/staging/src/k8s.io/kubectl/pkg/cmd/version/version.go

Lines 123 to 128 in d92b788

	if !o.ClientOnly && o.discoveryClient != nil {
	// Always request fresh data from the server
	o.discoveryClient.Invalidate()
	serverVersion, serverErr = o.discoveryClient.ServerVersion()
	versionInfo.ServerVersion = serverVersion
	}

The external testing is currently accounted for in e2e tests.

Which issue(s) this PR fixes:

Fixes: #102754

Special notes for your reviewer:

Does this PR introduce a user-facing change?

NONE

Additional documentation e.g., KEPs (Kubernetes Enhancement Proposals), usage docs, etc.:

[k8s-ci-robot]

@eddiezane: This issue is currently awaiting triage.

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[eddiezane]

/cc @brianpursley

[eddiezane]

/cc @knight42

[knight42]

/lgtm

This looks reasonable to me and I think this is the right way to address #102754.

/hold

@eddiezane just in case if you want others to review, please feel free to cancel the hold.

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: brianpursley, eddiezane, knight42

The full list of commands accepted by this bot can be found here.

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Needs approval from an approver in each of these files:

• staging/src/k8s.io/kubectl/OWNERS [eddiezane]

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[eddiezane]

/remove-hold